'uninfested' originates from the prefix 'un-' meaning 'not' and the word 'infest' from Latin 'infestare', where 'in-' meant 'into' and 'festus' meant 'hostile'.

'infestare' transformed into the Old French word 'infester', and eventually became the modern English word 'infest'. The prefix 'un-' was added to form 'uninfested'.

Initially, 'infest' meant 'to attack or disturb', and 'uninfested' has retained the meaning of 'not being attacked or disturbed'.